As is known in the art, one issue in continuous wave (CW) radars, such as FMCW and interrupted CW, is that part of the transmitted signal leaks through to the receiver and can degrade dynamic range performance. Usually in a CW radar, transmission and reception occur on the same antenna resulting in a direct path feedthrough. However, feedthrough can also occur in radars in which the transmitting antenna is separated from the receiving antenna, the target of interest is far from both, and some of the transmitted signal reflects from a cloud or other object entering the receiver ahead (in time) of the reflected target signal. The feedthrough can also mix with real target return to generate false intermodulation product targets.
Prior art techniques for addressing intermodulation products include increasing the third order intercept point (TOI) of low noise amplifiers in the front end of phased array antennas to reduce the level of the intermodulation product. However, this requires increasing the size of the LNAs and other receiver components, which can significantly increase cost, consumed power, and complexity.